Assessing resistance against macrocyclic lactones in gastro-intestinal nematodes in cattle using the faecal egg count reduction test and the controlled efficacy test

被引：26
作者：
De Graef, J. [1 ]
Sarre, C. [1 ]
Mills, B. J. [2 ]
Mahabir, S. [2 ]
Casaert, S. [1 ]
De Wilde, N. [1 ]
Van Weyenberg, M. [1 ]
Geldhof, P. [1 ]
Marchiondo, A. [2 ]
Vercruysse, J. [1 ]
Meeus, P. [2 ]
Claerebout, E. [1 ]
机构：
[1] Univ Ghent, Fac Vet Med, Parasitol Lab, B-9820 Merelbeke, Belgium
[2] Pfizer Anim Hlth, Kalamazoo, MI 49007 USA
来源：
VETERINARY PARASITOLOGY | 2012年 / 189卷 / 2-4期
关键词：
Ivermectin; Moxidectin; Resistance; Ostertagia ostertagi; Cooperia oncophora; Cattle; ANTHELMINTIC RESISTANCE; HAEMONCHUS-CONTORTUS; COOPERIA-ONCOPHORA; VETERINARY IMPORTANCE; OSTERTAGIA-OSTERTAGI; MOXIDECTIN; IVERMECTIN; INFECTIONS; ARGENTINA; HEALTH;
D O I：
10.1016/j.vetpar.2012.04.040
中图分类号：
R38 [医学寄生虫学]; Q [生物科学];
学科分类号：
07 ; 0710 ; 09 ; 100103 ;
摘要：
The main objective of the present study was to evaluate the accuracy of the faecal egg count reduction test (FECRT) to assess the resistance status of ivermectin (IVM)-resistant isolates of the cattle nematodes Ostertagia ostertagi and Cooperia oncophora, using the controlled efficacy test (worm counts) as a reference. The second objective was to investigate whether both IVM-resistant isolates showed side-resistance against moxidectin (MOX) under controlled conditions. Thirty male Holstein calves Were experimentally infected with 25,000 13 of an IVM-resistant O. ostertagi isolate and 25,00013 of an IVM-resistant C. oncophora isolate. Twenty-eight days later the calves were randomly divided into 2 treatment groups and 1 untreated control group. Animals in groups 1 and 2 received MOX (Cydectin (R) 1%, Pfizer) and IVM (Ivomec (R) 1%, Merial) respectively, by subcutaneous injection at a dose rate of 0.2 mg/kg bodyweight. Faecal samples were collected 7 and 14 days after treatment and animals were necropsied 14/15 days post-treatment. Both the FECRT and the controlled efficacy test demonstrated that the O. ostertagi and C. oncophora isolates were resistant , with efficacies below 90%. The IVM-resistant O. ostertagia isolate was still susceptible to MOX treatment, as shown by over 99% reduction in egg counts and worm burden. The FECRT suggested borderline resistance against MOX in the IVM-resistant C. oncophora isolate, with egg count reductions between 97% (95% CI: 76; 100) at day 7 and 86% (95% CI: 49; 96) at day 14. However, the controlled efficacy test clearly showed MOX-resistance, with a decrease of only 31% (95% CI: 12; 57) in C. oncophora worm numbers. After MOX treatment, a significantly lower number of eggs per female C oncophora worms was counted compared to the control group (43% reduction). Due to this reduced fecundity, the FECRT may fail to detect MOX-resistance. (C) 2012 Elsevier B.V. All rights reserved.
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页码：378 / 382
页数：5
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